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Updated: Sep 22, 2025

Influence of Hybrid Perovskite Fabrication Methods on Film Formation, Electronic Structure, and Solar Cell Performance
Published on: February 27, 2017
Intra- and Intermolecular Steric Hindrance Effects Induced Higher Open-Circuit Voltage and Power Conversion
Liangliang Han1, Weichao Chen1, Tong Hu2
1CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China.
Abstract:
A pair of donor-acceptor polymers PBDThDTBT and PBDTchDTBT are synthesized, which share the same conjugated backbone, but are designed with hexyl and cyclohexyl side chains, respectively. The stronger steric hindrance of cyclohexyl endows PBDTchDTBT a deeper lying HOMO energy level of -5.39 eV compared to -5.22 eV for PBDThDTBT. However, PBDThDTBT and PBDTchDTBT exhibit a similar optical bandgap around 1.72 eV and a hole mobility around 10-5 cm2 V-1 s-1. Interestingly, the PBDTchDTBT/PC71BM blends exhibited higher hole mobility than PBDThDTBT/PC71BM after DIO was added. The higher hole mobility and fibrillar network in the active layer endows PBDTchDTBT higher power conversion efficiency of 7.9%, together with simultaneously improved open-circuit voltage of 0.80 V, short-circuit current density of 13.50 mA cm-2, and fill factor of 72.74% after a systemic study of their solar cell devices.
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